private ReturnTracerResult TraceFrom(int startAt, LinqList <Label> path, LinqHashSet <Label> pathLookup)
{
ReturnTracerResult cached;
if (Cache.TryGetValue(startAt, out cached))
{
return(cached);
}
var nextBranches = Branches.Where(b => b.Item3 >= startAt).GroupBy(g => g.Item3).OrderBy(x => x.Key).FirstOrDefault();
var orReturn = Returns.Where(ix => ix >= startAt && (nextBranches != null ? ix < nextBranches.Key : true)).Count();
var orThrow = Throws.Where(ix => ix >= startAt && (nextBranches != null ? ix < nextBranches.Key : true)).Count();
if (orReturn != 0)
{
Cache[startAt] = cached = ReturnTracerResult.Success();
return(cached);
}
if (orThrow != 0)
{
Cache[startAt] = cached = ReturnTracerResult.Success();
return(cached);
}
if (nextBranches == null)
{
Cache[startAt] = cached = ReturnTracerResult.Failure(path);
return(cached);
}
var ret = new LinqList <ReturnTracerResult>();
foreach (var nextBranch in nextBranches)
{
if (pathLookup.Contains(nextBranch.Item2))
{
Cache[startAt] = cached = ReturnTracerResult.Success();
ret.Add(cached);
continue;
}
var branchOp = nextBranch.Item1;
var branchTo = Marks[nextBranch.Item2];
var removeFromPathAt = path.Count;
path.Add(nextBranch.Item2);
pathLookup.Add(nextBranch.Item2);
var fromFollowingBranch = TraceFrom(branchTo, path, pathLookup);
path.RemoveAt(removeFromPathAt);
pathLookup.Remove(nextBranch.Item2);
if (IsUnconditionalBranch(branchOp))
{
Cache[startAt] = cached = fromFollowingBranch;
//return cached;
ret.Add(cached);
continue;
}
var fromFallingThrough = TraceFrom(startAt + 1, path, pathLookup);
Cache[startAt] = cached = ReturnTracerResult.Combo(fromFallingThrough, fromFollowingBranch);
ret.Add(cached);
}
Cache[startAt] = cached = ReturnTracerResult.Combo(ret.ToArray());
return(cached);
}